CDM 2015 Explained for Subcontractors: Your Duties Under SI 2015/51

Last updated June 2025. Based on the Construction (Design and Management) Regulations 2015 (SI 2015/51) and HSE guidance. This page summarises CDM 2015 as it applies to subcontractors. It is not legal advice — always review and adapt to your specific site and task with a competent person.

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What CDM 2015 Actually Is — and Why Subcontractors Cannot Ignore It

The Construction (Design and Management) Regulations 2015 — formally Statutory Instrument 2015 No. 51 — are the primary health and safety framework for construction work in Great Britain, made under the Health and Safety at Work etc. Act 1974. (SI 2015/51)

Most published guides aim at clients, principal contractors, or project managers. That framing leaves working subcontractors — sole traders, small specialist firms, subbies engaged by a main contractor — trying to work out which bits actually apply to them. This page answers that question directly, regulation by regulation, for the party who has no direct client relationship and no site-wide coordination responsibility.

The short answer: CDM 2015 attaches duties to you personally, regardless of what the principal contractor (PC) does or does not do. Ignorance of those duties is not a defence.

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How CDM 2015 Defines 'Contractor' — and Why That Definition Captures Subcontractors

Here is the single most important point on this page: the word "subcontractor" does not appear anywhere in SI 2015/51. The statute uses the term "contractor".

The Regulations define a contractor as any person (including a self-employed person) who carries out, manages, or controls construction work. If you are a bricklayer, electrician, groundworker, painter, or any other tradesperson doing physical construction work on site — engaged by a main contractor rather than by the client directly — you are a "contractor" under CDM 2015. Your contractual tier does not change your statutory classification.

This matters because Part 3 of the Regulations sets out duties that attach to every contractor, including those in a subcontract position. Regulation 15 (Duties of contractors) applies to you. You do not step outside it because someone else holds the main contract.

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The Five Duties That Bind Every Subcontractor on Every Project

These duties derive from Regulation 15 and Regulation 8 of SI 2015/51. They apply on every construction project, notifiable or not.

1. Do not start work unless a construction phase plan exists (where one is required). On any project where a principal contractor has been appointed, you must not begin construction work unless you have been given the opportunity to see the relevant parts of the construction phase plan. You are not required to write it — that duty rests with the PC under Regulation 12 — but you must work in accordance with it.

2. Plan, manage, monitor, and control your own work. Regulation 15 requires every contractor to plan, manage, monitor, and control the construction work they carry out in a way that ensures, so far as is reasonably practicable, that it is carried out without risk to health or safety. This is the legal basis for task planning, risk assessment, briefing and safe-system-of-work evidence. RAMS are the standard industry document used to evidence that work, but the acronym itself is not named in CDM 2015.

3. Comply with general duties in Regulation 8. Regulation 8 imposes duties on all persons (including contractors) to comply with the specific requirements of Part 4 of the Regulations — the general site safety requirements covering things like safe places of work (Regulation 17), stability of structures (Regulation 19), excavations (Regulation 22), traffic routes (Regulation 27), fire prevention (Regulation 29), emergency procedures (Regulation 30), and welfare facilities as set out in Schedule 2.

4. Not employ or appoint a contractor unless satisfied they have the skills, training, and experience necessary. If you sub-sub-contract any element of your work, you take on a duty to check the competence of whoever you appoint.

5. Cooperate with the principal contractor and any other contractor sharing the site. This means attending inductions, following site rules set out in the construction phase plan, reporting hazards you identify, and not creating risks for others.

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Additional Duties That Apply on Notifiable Projects — and How to Know If Yours Is One

Regulation 6 of SI 2015/51 sets out the notifiability threshold. The duty to notify the relevant authority rests with the client, not with you. If the client has failed to notify, the duty may pass to the principal contractor — but it is never your duty as a subcontractor to submit the F10 notification.

What you should do on a notifiable project is confirm that notification has been made and record the project's notification reference in your site folder. Where a project involves, or is likely to involve, more than one contractor, a principal designer and a principal contractor must be appointed whether or not the project is notifiable. The existence of those appointments does not create new substantive duties for you personally beyond those in Regulation 15 — but it does mean:

• You will receive a construction phase plan, and must work in accordance with it.
• The PC has formal duties to consult you (Regulation 14) and you have a corresponding duty to cooperate.
• You must provide information to the PC for inclusion in the health and safety file where required.

How to check notifiability: Ask your PC directly whether the project meets the Regulation 6 notification threshold and, if it does, ask for the F10 notification reference. Do not infer notifiability from the existence of a principal contractor or principal designer; those appointments are required whenever there is, or is likely to be, more than one contractor.

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What the Principal Contractor Must Do — and What That Means for You in Practice

The table below maps the main CDM duties across the three parties a subcontractor encounters, using the regulation structure of SI 2015/51. It is designed to show what you can stop worrying about — and what you cannot.

Duty	YOU (Subcontractor / Contractor)	Principal Contractor	Client
Appoint PC and Principal Designer	✗ Not your duty	✗ Not their appointment to make	✓ Regulation 5
Submit F10 notification	✗ Confirm it exists, record reference	✗ Only if client fails	✓ Regulation 6
Prepare construction phase plan	✗ Work in accordance with it	✓ Regulation 12	✗
Produce RAMS for your own work	✓ Regulation 15 — your duty	✗ May review, cannot waive your duty	✗
Plan, manage, control your own work	✓ Regulation 15	✓ For site-wide coordination — Regulation 13	✗
Ensure welfare facilities exist	✓ Check and use — Schedule 2	✓ Provide — Regulation 13	✓ Regulation 4
Comply with Part 4 site safety requirements	✓ Regulation 8 — every person on site	✓ Regulation 8	✓ Regulation 8
Consult workers on health and safety	✗ (unless you employ workers yourself, separate legislation applies)	✓ Regulation 14	✗
Health and safety file	Provide information if requested	Compile and hand to client — Regulation 12	Receive and keep — Regulation 4

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The Paperwork Subcontractors Must Produce Under CDM 2015

CDM 2015 does not contain a list headed "documents subcontractors must produce". What it does is impose duties — and producing certain documents is how you evidence that the work has been planned, assessed, briefed and coordinated.

RAMS (Risk Assessment and Method Statement) Regulation 15 requires you to plan, manage, and control your work to eliminate or reduce risk so far as is reasonably practicable. A written RAMS is the standard industry mechanism for demonstrating that you have done this. Your PC will almost certainly require it before you start, but the underlying legal duty is to plan, assess, communicate and control the work.

Site induction record You must have received a site induction from the PC (Regulation 13 requires the PC to provide one). Keep a signed record that you attended.

Incident and near-miss reporting Regulation 15 requires you to report anything you become aware of that is likely to endanger health or safety to the PC. Separately, the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013 (RIDDOR) requires certain incidents to be reported to the enforcing authority. Confirm with your PC on day one what the site's reporting procedure is and who holds responsibility for submitting RIDDOR reports.

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Worked Example: Brickwork Subcontractor on a Notifiable Commercial Refurbishment

Scenario: Ahmed is a self-employed bricklayer engaged by a principal contractor (BuildCo) to carry out blockwork partition walls as part of a notifiable commercial office refurbishment. He has no workers of his own and is paid by BuildCo under a labour-only subcontract. The project is notifiable.

At mobilisation (before Ahmed sets foot on site):

• Ahmed asks BuildCo for confirmation that an F10 notification has been submitted and records the reference number in his site folder. (Regulation 6 — client/PC duty, but Ahmed confirms it.)
• Ahmed receives the relevant sections of BuildCo's construction phase plan covering the areas where he will work. He reads them and keeps a copy. (Regulation 12 — PC duty to prepare, Regulation 15 — Ahmed's duty to work in accordance with it.)
• Ahmed produces his RAMS covering blockwork, manual handling, dust (respirable crystalline silica), working at height for lintel placement, and tool safety. He submits it to BuildCo and keeps a copy acknowledging receipt. (Regulation 15.)
• Ahmed attends and signs the site induction. (Regulation 13 — PC duty to induct, Ahmed's duty to attend and cooperate.)

During work:

• Ahmed checks the welfare facilities on his first day — sanitary conveniences, washing facilities, drinking water, and rest area — as required by Schedule 2. If they are inadequate, he reports it to the PC.
• Ahmed notices an unprotected floor opening left by another trade. He reports it to the site manager in writing (a WhatsApp message is sufficient provided it is kept). (Regulation 15 — duty to report dangers to the PC.)
• Ahmed stores materials on a designated area shown in the construction phase plan and keeps his work area clear. (Regulation 18 — good order and site security; Regulation 15 — working in accordance with the CPP.)

At handover/completion:

• Ahmed provides BuildCo with any relevant information about his installed work — product data sheets for the mortar, block specifications — for potential inclusion in the health and safety file. (Regulation 12 — file compiled by PC.)
• Ahmed retains his RAMS and induction record for a reasonable period (best practice: at least three years).

What Ahmed does NOT have to do:

• Submit the F10 himself.
• Write the construction phase plan.
• Appoint a principal designer.
• Hold CHAS, SSIP, or any accreditation scheme registration — these are industry schemes, not requirements of SI 2015/51.

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Subcontractor CDM 2015 Site Folder Checklist

Print this page or save as PDF. One copy per project. Keep it at the front of your site folder.

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✅ SUBCONTRACTOR CDM 2015 SITE FOLDER CHECKLIST

Project name / address: _______________________________________________

Principal Contractor: _________________________________________________

My trade / scope of work: _____________________________________________

Date started on site: _________________________________________________

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#	Item	Reg. reference	Done ✓	Notes
1	Confirmed who the Principal Contractor is and have their contact details	Reg. 13
2	Confirmed F10 notification has been submitted; recorded reference number	Reg. 6 / Sched. 1
3	Received and read the relevant sections of the Construction Phase Plan	Reg. 12 / Reg. 15
4	RAMS submitted to PC and written acknowledgement received	Reg. 15
5	Site induction completed and signed record obtained	Reg. 13
6	Welfare facilities checked (sanitary, washing, drinking water, rest)	Sched. 2
7	Incident / near-miss reporting procedure confirmed with PC; know who reports to RIDDOR	Reg. 15
8	Site rules (from CPP) understood — access, traffic, emergency exits, fire points	Reg. 13 / Part 4
9	Any sub-sub-contractors appointed checked for competence	Reg. 15
10	Handover information (product data, as-built notes) provided to PC for H&S file	Reg. 12

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This checklist is a practical aide-memoire, not a substitute for reading SI 2015/51 or for site-specific risk assessment.

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Consequences of Non-Compliance — Enforcement, Prosecution, and Civil Liability

CDM 2015 is enforced as part of the wider health and safety legislative framework in Great Britain. On most construction sites, the Health and Safety Executive (HSE) is the enforcing authority; however, local authorities may enforce health and safety legislation in certain premises — so "HSE enforces CDM" is not a universal statement.

Inspectors have powers to issue improvement notices, prohibition notices, and to prosecute. Prosecution for breaches of health and safety legislation can result in significant fines and, for the most serious breaches, custodial sentences for individuals. Civil claims from injured workers may also follow from a failure to discharge your Regulation 15 duties.

The practical risk for a subcontractor is concrete: if an incident occurs on your work area and you cannot demonstrate that you planned, managed, and controlled your work, and that you had suitable risk assessment and method evidence in place, you are exposed — both to enforcement action and to civil liability — regardless of what the principal contractor did or did not do.

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Domestic Projects — Does CDM 2015 Apply When You Are Engaged by a Main Contractor?

This is one of the most misunderstood points in CDM 2015. The answer is: CDM 2015 applies to domestic projects, but the duties transfer differently under Regulation 7.

Critically: if you are engaged as a subcontractor by a main contractor (rather than directly by the homeowner), your Regulation 15 duties are unchanged. The duty-transfer provisions in Regulation 7 affect the client's duties, not yours. You must still plan, manage, and control your own work; you should still produce the risk assessment and method evidence requested for the job; and you must still work in accordance with whatever plan or site rules the contractor above you operates.

Do not assume that a domestic address means CDM does not apply to you.

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Frequently Asked Questions

Is a subcontractor ever treated as a 'contractor' under CDM 2015? Always. The statute uses only the word "contractor", and it captures anyone who carries out, manages, or controls construction work — regardless of contractual tier. There is no category called "subcontractor" in SI 2015/51.

What paperwork do I legally have to produce? CDM 2015 does not specify a list of documents. It requires you to plan, manage, and control your work (Regulation 15). In practice this usually means producing RAMS that are adequate for the task, keeping an induction record, and being able to show you worked in accordance with the construction phase plan.

When does CDM 2015 apply — are there projects it does not cover? CDM 2015 applies across Great Britain to virtually all construction work. It applies on domestic projects (with duty transfers under Regulation 7). Your Regulation 15 duties as a contractor apply on every project, notifiable or not.

What is the difference between my duties and the principal contractor's duties? See the comparison table above. In short: the PC coordinates site-wide health and safety, prepares the construction phase plan, and provides welfare and inductions. You plan, manage, and control your own work, provide the RAMS or equivalent task evidence the PC requires, and work in accordance with the PC's plan. Both sets of duties exist in parallel — the PC's duties do not substitute for yours.

What happens if I do not comply? You are exposed to HSE enforcement (improvement or prohibition notices, prosecution), significant fines, and civil liability claims from anyone injured as a result of your failure. The fact that a PC was also in breach does not remove your personal liability.

Do you need SSIP accreditation or a PQQ to work as a subcontractor under CDM 2015? Neither SSIP membership nor completion of a pre-qualification questionnaire (PQQ) is a statutory requirement under SI 2015/51 — there is no regulation that mandates a specific accreditation scheme. In practice, however, many PCs use Contractor Safety Questionnaires (CSQs) or SSIP-member schemes (such as CHAS, Constructionline, or SMAS) as a proportionate way to evidence the Regulation 8 competence check, and refusing or failing to engage with their chosen method will typically bar you from being awarded the subcontract. Prepare by keeping your health and safety documentation — current insurance, RAMS examples, training records, and operatives' card expiry dates — readily accessible and up to date, so you can respond to any standard questionnaire promptly and accurately.

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How RamsDocs Helps Subcontractors Produce Compliant RAMS Fast

This section describes a commercial product. It is separate from the regulatory content above.

Producing RAMS that evidence Regulation 15 planning does not always require a health and safety consultant. RamsDocs is built specifically for subcontractors and small contractors: answer a short set of task-specific questions and the platform generates a structured, PC review-ready RAMS document in under 10 minutes — pre-mapped to the duties in the checklist above.

Every RamsDocs output is designed to cover the planning and control obligations that Regulation 15 requires. You review it, adapt it to your specific site and task, and submit it to your PC with confidence.

Generate your RAMS with RamsDocs →

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Disclaimer: This page summarises selected provisions of the Construction (Design and Management) Regulations 2015 (SI 2015/51) for general information purposes. It is not legal advice. Regulatory requirements must be verified against the current text of SI 2015/51 at legislation.gov.uk. Any RAMS, checklist, or compliance document produced in connection with this page must be reviewed and adapted to your specific site, task, and workforce by a competent person before use. RamsDocs does not guarantee regulatory compliance or acceptance by any principal contractor or enforcing authority.